Otter (Lutrinae) Care Manual - Association of Zoos and Aquariums

Association of Zoos and Aquariums 136
Otter (Lutrinae) Care Manual
• Total coliform counts should not exceed 500 per ml water, or a MPN of 1000 coliform bacteria per
100ml water.
• Fecal coliform count should not exceed 400 per ml. If animal caretakers are routinely exposed to
pool water, an institution may establish a higher standard of 100 per ml, which is the level
considered safe for humans; this should be based on institutional policy.
Temperature: More detailed research is required into optimal water levels for the tropical otter species;
however, at this time the AZA Otter SSP recommends the following temperature guidelines:
A. cinereus: The water temperature for A. cinereus should be maintained between 18.3-29.4°C (65-85°F),
preferably at the warmer end of this scale (Petrini 1998).
A. capensis, L. canadensis: The water temperature for A. capensis and L. canadensis does not appear to
be critical.
L. maculicollis: Water temperature in successful L. maculicollis exhibits has ranged from 8.9-15.6°C (48-
60°F). Temperatures in the 15.6-21.1°C (60-70°F) range may encourage this species to spend more time
in the water, however, this is has not been objectively demonstrated at this time.
P. brasiliensis: Further study into optimal pool temperatures and water temperature exposure
recommendations for P. brasiliensis is required. Sykes-Gatz (2005) recommends this species should not
be allowed to swim in unheated water when air temperatures are below 5°C (41°F). Sufficient indoor
swim areas are needed when seasonal daytime air temperature regularly falls below 15°C (59°F),
regardless of whether outdoor water is heated. This is particularly true for family groups rearing pups that
may be held indoors for 4-5 months during cold temperatures. Heating of indoor housing pools is not
necessary if the ambient air temperature is maintained at recommended levels.
Each individual institution will have to determine whether their exhibit must be heated or chilled and
the most efficient way to do that.
Turnover Rate: The size and capacity of a life support system is based on turnover rate (the given unit
of time it takes the total amount of the exhibit water to pass through the filtration). This is usually given as
gallons per minute (GPM).
The turnover rate is based on the volume of the exhibit combined with the amount of organic matter
likely to be put into the water by the animals and the environment (leaves and branches, etc.). For
example, a hippopotamus pool is likely to require a much higher turnover rate than an otter in the exact
same sized pool. The dirtier the water is, the likelier a higher turnover rate should be employed.
A proper turnover rate is crucial as a system with a turnover rate that is too low will always be
laboring to catch up, and a system with a turnover rate that is too high is wasting money.
Filtration:
Biological Filtration: This is the use of bacterial colonies to convert ammonia to nitrite and then nitrate
through nitrification.
In aquariums with fish, ammonia and nitrite are harmful and should be kept as close to 0.0 as
possible. With the exception of certain invertebrates in salt water systems, nitrates are not considered
harmful. Otters should have no problem with ammonia and its derivatives, but an excess of nitrates in an
otter pool is undesirable as they are a primary source of nutrients for algae.
Nitrate levels can be kept in check with water changes or by a number of different denitrification
methods.
Mechanical Filtration: Mechanical filtration is the mechanical removal of particulate matter suspended in
the water column before it decomposes.
The matter is moved to the filter which is then cleansed. Until the filter is backwashed, the particulate
matter is still in the system. Rapid sand, screen, drum, bag, diatomaceous earth, protein skimmers and
bead filters are most commonly used in this application. Water clarity is most directly affected by the
quality of the mechanical filtration.
Chemical Filtration: The use of any filtering substance designed to chemically attract pollutants in order to
remove them from the water column.
• Activated Carbon